RF400 Series Spread Spectrum Data Radio/Modems
(CSI Item # 14291) with tinned leads to connect to power at the datalogger 12 V output terminals and barrel connector to plug into the RF400’s “DC Pwr” jack. If 120 VAC is available at the site, the 120 VAC adapter alone (CSI Item
# 15966) is an option.
A 12 V supply may connect to either the RF400’s “DC Pwr” jack or CS I/O pin 8 (or both, since there is diode isolation between supply inputs). The 12 V supply inputs are diode protected against the application of reverse polarity power.
CAUTION There are many AC adapters available with barrel connectors (plugs) that will fit the RF400. Some of these (including the CSI AC adapter Item # 272) will cause immediate damage if plugged into the RF400 even briefly. It is also possible to damage the RF400 with an AC adapter labeled as low as “12 VDC” because it may output an
The RF400 series radio will sustain damage if
the DC Pwr jack voltage ever exceeds 18
Volts!
120 VAC line voltages vary from location to location and from time to time so observing a 16.5 VDC maximum is wise. Unconsidered AC adapter selection raises the specter of
There are several things to consider. Beware of AC adapters outputting an AC voltage. An AC adapter can output the correct voltage but the wrong polarity. The center conductor of the barrel connector must be positive
(+). The AC adapter must also be capable of supplying the instantaneous peak currents demanded by the RF400 transmitter. The best approach is to obtain the AC adapter recommended by CSI (Item #15966 or the RF400 Base Station Cable/Power Kit Item # 14220 which contains it). If this is not possible, obtain an AC adapter that matches the voltage vs. current characteristics shown below.
To be sure that the candidate AC adapter’s “no load” voltage is below the 16.5 VDC recommended maximum, measure the output with a DC voltmeter while the AC adapter is plugged into the outlet but not powering anything.
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